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| United States Patent |
5,168,106
|
|
Babcock
, et al.
|
December 1, 1992
|
Carbon blacks
Abstract
Carbon blacks having a nitrogen surface area (N.sub.2 SA) of from at least
180 m.sup.2 /g to about 250 m.sup.2 /g, a ratio of nitrogen surface
area/iodine adsorption number (N.sub.2 SA/I.sub.2 No.) of from about 0.90
to about 1.05, a ratio of .DELTA.D 50/Dmode of from about 0.67 to about
0.81, a DBP (dibutyl phthalate number) of from about 115 cc/100 g to about
135 cc/100 g and a .DELTA.DBP [.DELTA.DBP=DBP-CDPB (Crushed DBP)] less
than or equal to 20 cc/100 g, and rubber compositions in which the carbon
blacks are incorporated.
| Inventors:
|
Babcock; Kenneth W. (Pampa, TX);
Zimmer; Jay J. (Brighton, AU)
|
| Assignee:
|
Cabot Corporation (Waltham, MA)
|
| Appl. No.:
|
406993 |
| Filed:
|
September 14, 1989 |
| Current U.S. Class: |
524/495; 423/445R |
| Intern'l Class: |
C01B 031/00; C08K 003/04 |
| Field of Search: |
423/445,451
524/495
|
References Cited
U.S. Patent Documents
| 4748199 | May., 1988 | Takiguchi et al. | 524/495.
|
| 4775778 | Oct., 1988 | van Konynenburg et al. | 524/495.
|
| 4871794 | Oct., 1989 | Itoh et al. | 524/495.
|
| 4886850 | Dec., 1989 | Ogawa et al. | 524/495.
|
| Foreign Patent Documents |
| 61-034072 | Feb., 1986 | JP | 423/445.
|
Primary Examiner: Lewis; Michael
Assistant Examiner: Hendrickson; Stuart L.
Attorney, Agent or Firm: Chaletsky; L. A., Gwinnell; H. J.
Claims
We claim:
1. Carbon blacks characterized by having a nitrogen surface area of at
least 180 m.sup.2 /g to about 250 m.sup.2 /g, a ratio of nitrogen surface
area/iodine adsorption number of from about 0.90 to about 1.05, a ratio of
.DELTA.D 50/Dmode of from about 0.67 to about 0.81, a DBP of from about
115 cc/100 g to about 135 cc/100 g and a .DELTA.DBP (DBP-CDBP) less than
or equal to 20 cc/100 g.
2. The carbon blacks of claim 1 wherein the nitrogen surface area is from
about 190 m.sup.2 /g to about 240 m.sup.2 /g.
3. The carbon blacks of claim 1 wherein .DELTA.DBP is from about 10 cc/100
g to about 20 cc/100 g.
4. The carbon blacks of claim 1 wherein the ratio of .DELTA.D 50/Dmode is
from about 0.70 to about 0.77.
5. The carbon blacks of claim 2 wherein the ratio of .DELTA.D 50/Dmode is
from about 0.70 to about 0.77 and .DELTA.DBP is from about 10 cc/100 g to
about 20 cc/100 g.
6. The carbon black of claim 1 wherein the nitrogen surface area is about
216 m.sup.2 /g, the ratio of nitrogen surface area/iodine adsorption
number is about 1.00, the ratio of .DELTA.D 50/Dmode is about 0.75, the
DBP is about 132 cc/100 g and the .DELTA.DBP is about 20 cc/100 g.
7. The carbon black of claim 1 wherein the nitrogen surface area is about
236 m.sup.2 /g, the ratio of nitrogen surface area/iodine adsorption
number is about 1.00, the ratio of .DELTA.D 50/Dmode is about 0.75, the
DBP is about 122 cc/100 g and the .DELTA.DBP is about 16 cc/100 g.
8. The carbon black of claim 1 wherein the nitrogen surface area is about
192 m.sup.2 /g, the ratio of nitrogen surface area/iodine adsorption
number is about 0.96, the ratio of .DELTA.D 50/Dmode is about 0.73, the
DBP is about 117 cc/100 g and the .DELTA.DBP is about 15 cc/100 g.
9. A rubber composition comprising about 100 parts, by weight, of a rubber
and from about 10 to about 250 parts, by weight, of a carbon black having
a nitrogen surface area of at least 180 m.sup.2 /g to about 250 m.sup.2
/g, a ratio of nitrogen surface area/iodine adsorption number of from
about 0.90 to about 1.05, a ratio of .DELTA.D 50/Dmode of from about 0.67
to about 0.81, a DBP of from about 115 cc/100 g to about 135 cc/100 g and
a .DELTA.DBP (DBP-CDBP) less than or equal to 20 cc/100 g.
10. The rubber composition of claim 9 wherein the nitrogen surface area of
the carbon blacks is from about 190 m.sup.2 /g to about 240 m.sup.2 /g.
11. The rubber composition of claim 9 wherein the .DELTA.DBP of the carbon
blacks is from about 10 cc/100 g to about 20 cc/100 g.
12. The rubber composition of claim 9 wherein the ratio of .DELTA.D
50/Dmode of the carbon blacks is from about 0.70 to about 0.77.
13. The rubber composition of claim 10 wherein the ratio of .DELTA.D
50/Dmode of the carbon blacks is from about 0.70 to about 0.77 and
.DELTA.DBP of the carbon blacks is from about 10 cc/100 g to about 20
cc/100 g.
14. The rubber composition of claim 9 wherein the nitrogen surface area of
the carbon black is about 216 m.sup.2 /g, the ratio of nitrogen surface
area/iodine adsorption number of the carbon black is about 1.00, the ratio
of .DELTA.D 50/Dmode of the carbon black is about 0.75, the DBP of the
carbon black is about 132 cc/100 g and the .DELTA.DBP of the carbon black
is about 20 cc/100 g.
15. The rubber composition of claim 9 wherein the nitrogen surface area of
the carbon black is about 236 m.sup.2 /g, the ratio of nitrogen surface
area/iodine adsorption number of the carbon black is about 1.00, the ratio
of .DELTA.D 50/Dmode of the carbon black is about 0.75, the DBP of the
carbon black is about 122 cc/100 g and the .DELTA.DBP of the carbon black
is about 16 cc/100 g.
16. The rubber composition of claim 9 wherein the nitrogen surface area of
the carbon black is about 192 m.sup.2 /g, the ratio of nitrogen surface
area/iodine adsorption number of the carbon black is about 0.96, the ratio
of .DELTA.D 50/Dmode of the carbon black is about 0.73, the DBP of the
carbon black is about 117 cc/100 g and the .DELTA.DBP of the carbon black
is about 15 cc/100 g.
17. The rubber composition of claim 9 wherein the rubber is natural rubber.
18. The rubber composition of claim 9 wherein the rubber is synthetic
rubber.
19. The rubber composition of claim 9 wherein the carbon black is present
in an amount of from about 20 to about 100 parts by weight per 100 parts
by weight rubber.
20. The rubber composition of claim 9 wherein the carbon black is present
in an amount of from about 40 to about 80 parts by weight per 100 parts by
weight rubber.
Description
FIELD OF THE INVENTION
The present invention relates to a class of new and novel furnace carbon
blacks which are suitable for various applications and particularly well
suited for use in rubber compositions.
BACKGROUND
Carbon blacks are generally produced in a furnace-type reactor by
pyrolyzing a hydrocarbon feedstock with hot combustion gases to produce
combustion products containing particulate carbon black.
Carbon blacks may be utilized as pigments, fillers, reinforcing agents and
for a variety of other applications. For example, carbon blacks are widely
utilized as fillers and reinforcing pigments in the compounding and
preparation of rubber compositions. Most importantly, carbon blacks are
effective in the preparation of rubber vulcanizates intended for usage in
preparing tires. It is generally desirable in the production of tires to
utilize carbon blacks which produce tires with satisfactory handling and
cornering properties, abrasion resistance, and traction (wet and dry skid
resistance). In particular, it is desirable to produce blacks capable of
imparting improved properties of these types for use in high performance
tires and racing tires.
Accordingly, one object of the present invention is the production of new
carbon blacks which impart improved handling and cornering, increased
abrasion resistance and improved traction properties to natural rubbers,
synthetic rubbers and blends of natural and synthetic rubbers
incorporating the carbon blacks.
Another object of the present invention is new rubber compositions,
advantageous for use as high performance and racing tires, incorporating
the new carbon blacks.
Other objects of the present invention will become apparent from the
following description and the claims.
SUMMARY OF THE INVENTION
We have discovered a new class of carbon blacks having a nitrogen surface
area (N.sub.2 SA) of at least 180 m.sup.2 /g (square meters per gram) to
about 250 m.sup.2 /g, preferably of from about 190 m.sup.2 /g to about 240
m.sup.2 /g, a ratio of nitrogen surface area/iodine Adsorption number
(N.sub.2 SA/I.sub.2 No.) of from about 0.90 to about 1.05, a ratio of
.DELTA.D 50/Dmode of from about 0.67 to about 0.81, preferably of from
about 0.70 to about 0.77, a DBP (dibutyl phthlate number) of from about
115 cc/100 g (cubic centimeters per 100 grams) to about 135 cc/100 g and a
.DELTA.DBP [.DELTA.DBP=DBP-CDBP (Crushed DBP)] less than or equal to 20
cc/100 g, preferably from about 10 cc/100 g to about 20 cc/100 g. We have
also discovered a new class of rubber compositions containing these carbon
blacks.
The carbon blacks of the present invention may be produced in a furnace
carbon black reactor having a first (combustion) zone, and a reaction zone
separated by at least two zones, hereinafter referred to as feedstock
injection zones, into which a carbon black yielding feedstock is injected
in any manner known to the art, into a hot combustion gas stream. The
resultant mixture of hot combustion gases and feedstock passes into the
reaction zone. Pyrolysis, of the carbon black yielding feedstock, is
stopped by quenching the mixture when the carbon blacks of the present
invention have been formed. Preferably pyrolysis is stopped by a quench
injecting a quenching fluid. The process for preparing the novel carbon
blacks of the present invention will be described in greater detail
hereinafter.
The rubbers for which the novel carbon blacks of this invention are
effective as reinforcing agents include natural and synthetic rubbers.
Generally, amounts of the carbon black product ranging from about 10 to
about 250 parts by weight can be used for each 100 parts by weight of
rubber in order to impart a significant degree of reinforcement thereto.
It is, however, preferred to use amounts varying from about 20 to about
100 parts by weight of carbon black per 100 parts by weight of rubber and
especially preferred is the utilization of from about 40 to about 80 parts
of carbon black per 100 parts of rubber.
Among the rubbers suitable for use with the present invention are natural
rubber and its derivatives such as chlorinated rubber; copolymers of from
about 10 to about 70 percent by weight of styrene and from about 90 to
about 30 percent by weight of butadiene such as copolymer of 19 parts
styrene and 81 parts butadiene, a copolymer of 30 parts styrene and 70
parts butadiene, a copolymer of 43 parts styrene and 57 parts butadiene
and a copolymer of 50 parts styrene and 50 parts butadiene; polymers and
copolymers of conjugated dienes such as polybutadiene, polyisoprene,
polychloroprene, and the like, and copolymers of such conjegated dienes
with an ethylenic group-containing monomer copolymerizable therewith such
as styrene, methyl styrene, chlorostyrene, acrylonitrile,
2-vinyl-pyridine, 5-methyl-2-vinylpyridine, 5-ethyl-2-vinylpyridine,
2-methyl-5-vinylpyridine, alkyl-substituted acrylates, vinyl ketone,
methyl isopropenyl ketone, methyl vinyl ether, alphamethylene carboxylic
acids and the esters and amides thereof such as acrylic acid and
dialkylacrylic acid amide; also suitable for use herein are copolymers of
ethylene and other high alpha olefins such as propylene, butene-1 and
penetene-1; particularly preferred are the ethylene-propylene copolymers
wherein the ethylene content ranges from 20 to 90 percent by weight and
also the ethylene-propylene polymers which additionally contain a third
monomer such as dicyclopentadiene, 1,4-hexadiene and methylene norbornene.
An advantage of the carbon blacks of the present invention is that the
carbon blacks impart improved handling and cornering properties, increased
abrasion resistance and improved traction to compositions containing
natural rubbers, synthetic rubbers or blends thereof in which the carbon
blacks of the present invention are incorporated.
An advantage of the rubber compositions of the present invention is the
that the rubber compositions are particularly well suited for use as high
performance and racing tires.
Other advantages of the present invention will become apparent from the
following more detailed description of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a portion of one type of furnace carbon
black reactor which may be utilized to produce the carbon blacks of the
present invention.
FIG. 2 is a graph with an example of a Stokes diameter distribution curve.
DETAILED DESCRIPTION OF THE INVENTION
The carbon blacks of the present invention are characterized by having a
N.sub.2 SA of at least 180 m.sup.2 /g to about 250 m.sup.2 /g, preferably
of from about 190 m.sup.2 /g to about 240 m.sup.2 /g, a N.sub.2 SA/I.sub.2
No. ratio of from about 0.90 to about 1.05, a ratio of .DELTA.D50/Dmode of
from about 0.67 to about 0.81, preferably of from about 0.70 to about
0.77, a DBP of from about 115 cc/100 g to about 135 cc/100 g and a
.DELTA.DBP less than or equal to 20 cc/100 g, preferably from about 10
cc/100 g to about 20 cc/100 g.
The carbon blacks of the present invention may be produced in a modular,
also referred to as "staged", furnace carbon black reactor. section of a
typical modular furnace carbon black reactor which may be utilized to
produce the carbon blacks of the present invention is depicted in FIG. 1.
Referring to FIG. 1, the carbon blacks of the present invention may be
produced in a furnace carbon black reactor 2, having a combustion zone 10,
which has a zone of converging diameter 11; feedstock injection zones 12
and 14; and reaction zone 18. The diameter of the combustion zone, 10, up
to the point where the zone of converging diameter, 11, begins is shown as
D-1; the diameter of the converging zone, at the narrowest point, is shown
as D-2; the diameter of zone 12, as D-3; the diameter of zone 14, as D-4;
and the diameter of the reaction zone, 18, as D-5. The carbon blacks of
the examples described herein of the present invention were produced in a
reactor where D-1 is 20 inches; D-2 is 5.5 inches; D-3 is 4.5 inches; D-4
is 5.3 inches; and D-5 is 13.5 inches.
To produce the carbon blacks of the present invention hot combustion gases
are generated in combustion zone 10 by contacting a liquid or gaseous fuel
with a suitable oxidant stream such as air, oxygen, mixtures of air and
oxygen or the like. Among the fuels suitable for use in contacting the
oxidant stream in combustion zone, 10, to generate the hot combustion
gases are included any of the readily combustible gas, vapor or liquid
streams such as natural gas, hydrogen, carbon monoxide, methane,
acetylene, alcohols, or kerosene. It is generally preferred, however, to
utilize fuels having a high content of carbon-containing components and in
particular, hydrocarbons. The ratio of air to fuel utilized to produce the
carbon blacks of the present invention may be from about 10:1 to about
20:1. To facilitate the generation of hot combustion gases, the oxidant
stream may be preheated.
The hot combustion gas stream flows downstream from zones 10 and 11 into
zones 12, 14 and then 18. The direction of the flow of hot combustion
gases is shown in the figure by the arrow. Carbon black-yielding
feedstock, 30, is introduced at point 32 (located in zone 12) and at point
34 (located in zone 14). To produce the carbon blacks of the present
invention, the feedstock may be injected in an amount of from about 50% to
about 80%, by weight, at point 32, and the remainder of the total amount
of from about 20% to about 50%, by weight, injected at point 34.
Preferably from about 70% to about 80% of the total amount of feedstock,
by weight, is introduced at point 32, and the remainder of the total
amount of feedstock, from about 30% to about 20%, by weight, is introduced
at point 34. In the examples described herein carbon black-yielding
feedstock, 30, was injected substantially transversely from the periphery
of the stream of hot combustion gases in the form of a plurality of jets
which penetrate into the interior regions of the hot combustion gas stream
to insure a high rate of mixing and shearing of the hot combustion gases
and the carbon black-yielding feedstock so as to rapidly and completely
decompose and convert the feedstock to the novel carbon blacks of the
present invention. The distance between point 32 and point 34 is shown in
the figure as L-1. The carbon blacks of the examples described herein of
present invention were produced in a carbon black reactor where L-1 is 18
inches.
The mixture of carbon black-yielding feedstock and hot combustion gases
flows downstream through zones 12 and 14, into reaction zone 18. Quench
40, located at point 42, injecting quenching fluid 50, is utilized to stop
pyrolysis of the carbon black-yielding feedstock when the novel carbon
blacks of the present invention are formed. Point 42 may be determined in
any manner known to the art, for selecting the position of a quench to
stop pyrolysis. One method for determining the position of the quench to
stop pyrolysis is by determining the point at which an acceptable toluene
extract level for the novel carbon blacks of the present invention is
achieved. Toluene extract level may be measured by using ASTM Test
D1618-83 "Carbon Black Extractables--Toluene Discoloration". L-2 is the
distance from the beginning of zone 18 to quench point 42, and will vary
according to the position of the quench.
After the mixture of hot combustion gases and carbon black-yielding
feedstock is quenched, the cooled gases pass downstream into any
conventional cooling and separating means whereby the carbon blacks are
recovered. The separation of the carbon black from the gas stream is
readily accomplished by conventional means such as a precipitator, cyclone
separator or bag filter.
The following testing procedures are used in the determination and
evaluation of the analytical properties of the carbon blacks of the
present invention, and the physical properties of the rubber compositions
incorporating the carbon blacks of the present invention.
Nitrogen surface area of the carbon blacks (N.sub.2 SA) was determined
according to ASTM D3037 Method A. Iodine adsorption number of the carbon
blacks (I.sub.2 No.) was determined according to JIS K 6221. Tinting
strength (Tint) of the carbon blacks was determined according to ASTM Test
Procedure D3265-85a. The DBP (Dibutyl Phthalate) of the carbon black
pellets was determined according to the procedure set forth in JIS K 6221
Method A. The CDBP (Crushed Dibutyl Phthalate) of the carbon black pellets
was determined by crushing the carbon black pellets according to the
procedure set forth in ASTM D 3493 and then determining DBP according to
JIS K 6221 Method A.
.DELTA.D 50 of the carbon blacks was determined in the following manner. A
histogram is made of the Stokes diameter of the aggregates of the carbon
black sample versus the relative frequency of their occurrence in a given
sample. As shown in FIG. 2, a line (B) is drawn from the peak (A) of the
histogram in a direction parallel to the Y axis, to and ending at the
X-axis at point (C) of the histogram. The midpoint (F) of the resultant
line (B) is determined and a line (G) is drawn through the midpoint (F)
thereof parallel to the X-axis. Line (G) intersects the distribution curve
of the histogram at two points D and E. The absolute value of the
difference of the two Stokes diameters of the carbon black particles at
points D and E is the D 50 value. The data used to generate the histogram
are determined by the use of a disk centrifuge such as the one
manufactured by Joyce Loebl Co. Ltd. of Tyne and Wear, United Kingdom. The
following procedure is a modification of the procedure described in the
instruction manual of the Joyce Loebl disk centrifuge file reference DCF
4.008 published on Feb. 1, 1985,the teachings of which are hereby
incorporated by reference, and was used in determining the data.
The procedure is as follows. 10 mg (milligrams) of a carbon black sample
are weighed in a weighing vessel, then added to 50 cc of a solution of 10%
absolute ethanol and 90% distilled water which is made 0.05% NONIDET P-40
surfactant (NONIDET P-40 is a registered trademark for a surfactant
manufactured and sold by Shell Chemical Co.). The resulting suspension is
dispersed by means of ultrasonic energy for 15 minutes using Sonifier
Model No. W 385, manufactured and sold by Heat Systems Ultrasonics Inc.,
Farmingdale, New York.
Prior to the disk centrifuge run the following data are entered into the
computer which records the data from the disk centrifuge:
1. The specific gravity of carbon black, taken as 1.86 g/cc;
2. The volume of the solution of the carbon black dispersed in a solution
of water and ethanol, which in this instance is 0.5 cc.;
3. The volume of spin fluid, which in this instance is 10 cc of water;
4. The viscosity of the spin fluid, which in this instance is taken as
0.933 centipoise at 23 degrees C.;
5. The density of the spin fluid, which in this instance is 0.9975 g/cc at
23 degrees C.;
6. The disk speed, which in this instance is 8000 rpm;
7. The data sampling interval, which in this instance is 1 second.
The disk centrifuge is operated at 8000 rpm while the stroboscope is
operating. 10 cc of distilled water are injected into the spinning disk as
the spin fluid. The turbidity level is set to 0; and 1 cc of the solution
of 10% absolute ethanol and 90% distilled water is injected as a buffer
liquid. The cut and boost buttons of the disk centrifuge are then operated
to produce a smooth concentration gradient between the spin fluid and the
buffer liquid and the gradient is monitored visually. When the gradient
becomes smooth such that there is no distinguishable boundary between the
two fluids, 0.5 cc of the dispersed carbon black in aqueous ethanol
solution is injected into the spinning disk and data collection is started
immediately. If streaming occurs the run is aborted. The disk is spun for
20 minutes following the injection of the dispersed carbon black in
aqueous ethanol solution. Following the 20 minutes of spinning, the disk
is stopped, the temperature of the spin fluid is measured, and the average
of the temperature of the spin fluid measured at the beginning of the run
and the temperature of the spin fluid measured at the end of the run is
entered into the computer which records the data from the disk centrifuge.
The data is analyzed according to the standard Stokes equation and is
presented using the following definitions:
Carbon black aggregate--a discrete, rigid colloidal entity that is the
smallest dispersible unit; it is composed of extensively coalesced
particles;
Stokes diameter--the diameter of a sphere which sediments in a viscous
medium in a centrifugal or gravitational field according to the Stokes
equation. A non-spherical object, such as a carbon black aggregate, may
also be represented in terms of the Stokes diameter if it is considered as
behaving as a smooth, rigid sphere of the same density and rate of
sedimentation as the non-spherical object. The customary units are
expressed in nanometer diameters.
Mode (Dmode for reporting purposes)--The Stokes diameter at the point of
the peak (Point A of FIG. 2 herein) of the distribution curve of Stokes
diameter.
Median Stokes diameter--(Dst for reporting purposes) the point on the
distribution curve of Stokes diameter where 50% by weight of the sample is
either larger or smaller (Point H of FIG. 2 herein). It therefore
represents the median value of the determination.
Rubber compositions incorporating the novel carbon blacks of the present
invention were prepared according to the SBR recipe shown in ASTM D
3191-83.
The cure characteristics of the rubber compositions were measured using a
Moving Die Rheometer (MDR). The cure temperature was set at 293 degrees F.
To test a sample, a 6 gram sample of the uncured rubber composition was
sealed within a cavity formed by the upper and lower dies of the MDR. The
bottom die was driven at 100 cycles/min. through 1 arc degree. The
resultant force transferred through the sample to the upper die is
measured by a reaction torque transducer. .tau.min is the minimum torque
value recorded during a test. .tau.max is the maximum torque value
recorded during a test. .DELTA..tau. is the difference between .tau.max
and .tau.min and represents the amount of crosslinking density generated
during a test. T.sub.2 is the time for a 2 inch-pound rise in the torque
value during a test. T.sub.90 is the time for a 90% increase in the cure
state to take place during a test.
The abrasion data of the rubber compositions were determined using an
abrader which is based on a Lambourn type machine. Abrasion rates (cubic
centimeter/centimeter travel) were measured at 7%, 13% and 21% slip. The
slip is based on the relative velocity of the plates rather than angle of
slip. In the following examples, the abrasion index is the ratio of the
abrasion rate of a control composition containing VULCAN 9 carbon black, a
trademarked product of Cabot Corporation, Waltham, Massachusetts divided
by the abrasion rate of a composition produced using a specified carbon
black of the present invention, at the same slip.
The hardness of the rubber compositions was measured by the procedure set
forth in ASTM D 2240. The modulus, tensile and elongation of the rubber
compositions were measured by the procedure set forth in ASTM D 412.
The dynamic mechanical properties of the rubber compositions were
determined in a manner well known to those of ordinary skill in the art,
using an Instron Model 1350 Servohydraulic System interfacing with a
Digital Equipment Corporation Minc-23 computer for data manipulation. The
specimen tested for each of the rubber compositions consisted of a
sandwich type test specimen comprising four pieces of each rubber
composition, each piece having the dimensions 30 mm by 30 mm by 6 mm
thick. The dynamic mechanical properties measured were complex modulus
(G*), elastic modulus (G'), and loss modulus (G"). Since the viscoelastic
properties of carbon black reinforced rubber compositions are temperature,
frequency and strain dependent, the measurements were done at two
temperatures, 70 degrees C. and 0.0 degrees C., 1 Hertz, and three
strains, 5%, 10% and 20%.
The loss tangent (tan delta) of a test piece, 30 mm by 5 mm by 2 mm thick,
of each of the SBR compositions was determined by measurement in a
visco-elastic spectrometer VES-S type made by Iwamoto Seisakusho Co., at a
temperature of 70 degrees C., a frequency of 10 Hz and a deformation of
2%.
The effectiveness and advantages of the present invention will be further
illustrated by the following examples.
EXAMPLES 1-3
Three examples of the novel carbon blacks of the present invention were
prepared in three different carbon black production runs, in a reactor
generally described herein, and as depicted in FIG. 1, utilizing the
reactor conditions and geometry set forth in Table I. The fuel utilized in
the combustion reaction in each example was natural gas, having a methane
content of 84.58 mol. % and a wet heating value of 973 BTU/SCF at standard
conditions (14.65 psia, 60.degree. F.). The liquid feedstock utilized in
each example was Conoco LC oil which had the following properties:
______________________________________
Feedstock Properties
______________________________________
Hydrogen/Carbon Ratio 0.94
Hydrogen (wt. %) 7.34
Carbon (wt. %) 92.5
Sulfur (wt. %) 0.5
A.P.I. Gravity 15.5/15.6 C(60)F [ASTM D-287]
-1.9
Specific Gravity 15.5/15.6 C(60)F [ASTM D-287]
1.092
Viscosity, SUS (130.degree. F.) [ASTM D-88]
94.2
Viscosity, SUS (210.degree. F.) [ASTM D-88]
39.3
BMCI (Visc-Grav) 136
______________________________________
TABLE I
______________________________________
CARBON BLACKS
Example 1
Example 2 Example 3
______________________________________
D-1, in. 20 20 20
D-2, in. 5.5 5.5 5.5
D-3, in. 4.5 4.5 4.5
D-4, in. 5.3 5.3 5.3
D-5, in. 13.5 13.5 13.5
L-1, in. 18 18 18
L-2, ft. 4.5 7.5 7.5
Oil Inj. Pt. 32,)
3 .times. 0.020
3 .times. 0.020
3 .times. 0.020
& & &
Tips # .times. Size, in.)
3 .times. 0.025
3 .times. 0.025
3 .times. 0.025
Oil Rate Pt. 32, gph
67 67 72
Oil Press. Pt. 32, psig
218 225 260
Oil Preheat Pt. 32, .degree.F.
310 305 310
Oil Inj. Pt. 34,)
3 .times. 0.020
3 .times. 0.020
3 .times. 0.020
Tips # .times. Size, in.)
Oil Rate Pt. 34, gph
22 23 23
Oil Press. Pt. 34, psig
104 130 130
Oil Preheat Pt. 34, .degree.F.
250 240 240
Comb. Air, kscfh
80.0 80.0 80.0
Comb. Air Preheat, .degree.F.
970 975 970
Natural Gas, kscfh
6.15 6.15 6.15
Air to Burn Ratio
9.1 9.1 9.1
Potassium, lb./hr.
5.5 20.0 26.0
Quench Press., psi
60 57 55
Temp. at Quench, .degree.F.
1350 1350 1350
______________________________________
Inj. = Injection
Comb. = combustion
Press. = pressure
Pt. 32 = Point 32 on FIG. 1
Pt. 34 = Point 34 on FIG. 1
gph = gallons per hour
psi = pounds per square inch
kscfh = standard cubic feet per hour, in thousands
in. = inches
ft. = feet
.degree.F. = degrees Fahrenheit
The carbon blacks produced in each run were then analyzed according to the
procedures described herein. The analytical properties of the blacks
produced in each run, as well as those of an SAF type carbon black control
sample, were as follows:
______________________________________
Carbon Black
Exam- Exam- Exam-
ple 1 ple 2 ple 3 SAF
______________________________________
.DELTA.D 50 (nm)
48 45 45 61
Dmode (nm) 64 60 62 80
.DELTA.D 50/Dmode
0.75 0.75 0.73 0.76
N.sub.2 SA (m.sup.2 /g)
216 236 192 144
I.sub.2 No. (m.sup.2 /g)
215 236 200 146
Tint (%) 142 144 143 125
DBP (cc/100 g)
132 122 117 115
CDBP (cc/100 g)
112 106 102 96
.DELTA.DBP (cc/100 g)
20 16 15 19
N.sub.2 SA/I.sub.2 No.
1.00 1.00 0.96 0.99
______________________________________
EXAMPLE 4
This Example illustrates the use of the novel carbon blacks of the present
invention in rubber compositions. Four carbon blacks were evaluated in
rubber compositions. Sample 1 was the carbon black of Example 1. Sample 2
was the carbon black of Example 2. Sample 3 was the carbon black of
Example 3. Sample 4 was the control SAF (Super Abrasion Furnace) type
carbon black.
Rubber compositions A, B, C and D were prepared incorporating each of the
carbon black samples according to the ASTM-SBR procedure. The rubber
compositions were as shown in Table II (all quantities shown as parts by
weight):
TABLE II
______________________________________
Rubber Composition
A B C D
______________________________________
SBR-1500 100 100 100 100
Carbon Black of
50
Example 1
Carbon Black of 50
Example 2
Carbon Black of 50
Example 3
SAF Type 50
Carbon Black
Zinc Oxide 3 3 3 3
Stearic Acid 1 1 1 1
TBBS* 1 1 1 1
Sulfur 1.75 1.75 1.75 1.75
______________________________________
*TBBS = Ntert-butyl-2-benzothiazole sulfenamide
The loss tangent (tan delta) of each of the rubber compositions was then
measured. The tan delta values of the rubber compositions were as follows:
______________________________________
Rubber Composition
A B C D
______________________________________
tan delta 0.246 0.263 0.241
0.201
______________________________________
These results clearly demonstrate that rubber compositions A, B and C,
produced with the carbon blacks of the present invention have higher
values for tan delta as compared to the control composition D, produced
with the conventional SAF type carbon black. This, in turn, indicates that
the rubber compositions of the present invention will have higher
hysteresis resulting in improved traction in high performance and racing
tires.
EXAMPLE 5
This Example illustrates that the effects resulting from the use of the
novel carbon blacks of the present invention in rubber compositions are
caused by the novel carbon blacks and not by any difference in the
crosslinking density (.DELTA..tau.) of the rubber compositions. Utilizing
the same carbon blacks of Examples 1, 2, and 3, and the same SAF type
control black, four rubber compositions E, F, G and H were prepared
according to the ASTM-SBR procedure except that the amount of TBBS was
varied depending on the particular carbon black utilized. The rubber
compositions were as shown in Table III (all quantities shown as parts by
weight):
TABLE III
______________________________________
Rubber Composition
E F G H
______________________________________
SBR-1500 100 100 100 100
SAF Type 50
Carbon Black
Carbon Black 50
of Example 1
Carbon Black 50
of Example 2
Carbon Black 50
of Example 3
Zinc Oxide 3 3 3 3
Stearic Acid
1 1 1 1
TBBS* 1 1.04 1.08 1.04
Sulfur 1.75 1.75 1.75 1.75
______________________________________
*TBBS = Ntert-butyl-2-benzothiazole sulfenamide
As shown in Table III, the TBBS ingredient in each rubber composition, E,
F, G, and H, was adjusted so that the crosslinking density (.DELTA..tau.)
would be substantially similar for all the rubber compositions.
The static properties of the SBR compositions were then evaluated according
to the ASTM procedures described herein. The results were as follows:
______________________________________
Modulus Modulus
Rubber 100% El* 300% El Tensile
El.sub.b *
Composition
Hardness (psi) (psi) (psi) (%)
______________________________________
E 65 470 2742 4053 394
F 69 498 2589 3976 417
G 70 415 2205 3392 406
H 70 483 2532 3285 358
______________________________________
*El = elongation; El.sub.b = elongation at break;
psi = pounds/square inch
These results show that the static properties of the rubber compositions F,
G, and H produced with the carbon blacks of the present invention are
comparable to those of rubber composition E, produced with an SAF type
carbon black.
The cure characteristics of the rubber compositions, all of which were
cured at 293.degree. F. using MDR, were then evaluated according to the
procedure described herein. The results were as follows:
______________________________________
Rubber T min T max .DELTA.T
T.sub.2
T.sub.90
Composition
(lb-in.)
(lb-in.) (lb-in.)
(min) (min)
______________________________________
E 10.7 49.4 38.7 12.16 37.46
F 14.7 54.5 39.8 12.04 41.4
G 13.9 53.4 39.5 12.05 40.71
H 12.6 52.6 40 12.64 41.98
______________________________________
lb-in. = poundinch; min = minutes
As will be understood by those of ordinary skill in the art, the
.DELTA..tau. values shown above indicate that the rubber compositions E,
F, G, and H have comparable crosslinking densities.
The Laboratory Abrasion Index of each SBR composition was also evaluated as
described herein. The results were as follows:
______________________________________
Rubber 7% Slip 13% Slip 21% Slip
Composition
(cc/cm trav)
(cc/cm trav)
(cc/cm trav)
______________________________________
E 100 100 100
F 127 119 120
G 125 112 107
H 121 115 109
______________________________________
cc/cm trav = cubic centimeters per centimeters travel
The laboratory abrasion index data show that the rubber compositions, F, G,
and H, containing the carbon blacks of the present invention, exhibit
significantly higher abrasion resistance than the rubber composition, E,
containing the SAF type contol carbon black.
The dynamic mechanical properties of the SBR compositions were also
evaluated at 1 Hertz, both at 0.0 degrees C., and 70 degrees C., as
described herein and the results were as follows:
______________________________________
G* G* G* G" G" G"
Shear (MPa) (MPa) (MPa) (MPa) (MPa) (MPa)
Strain.fwdarw.
5% 10% 20% 5% 10% 20%
______________________________________
DYNAMIC MECHANICAL PROPERTIES 0.degree. C., 1 Hz
E 4.98 4.06 3.23 1.04 0.86 0.63
F 6.64 5.14 3.84 1.6 1.29 0.89
G 6.81 5.12 3.96 1.63 1.33 1.0
H 5.75 4.51 3.66 1.24 1.06 0.86
DYNAMIC MECHANICAL PROPERTIES 70.degree. C., 1 Hz
E 2.58 2.32 1.99 0.32 0.26 0.19
F 3.03 2.57 2.10 0.48 0.37 0.25
G 2.92 2.49 2.16 0.49 0.38 0.29
H 2.91 2.51 2.19 0.46 0.35 0.28
______________________________________
MPa = megapascals
G*, the dynamic complex modulus, represents the cornering and handling
stiffness of a rubber tire tread composition. High cornering and handling
stiffness is important for high performance and racing tire treads. As
shown by the above results, the G* values for the rubber compositions, F,
G, and H, containing the carbon blacks of the present invention, are
significantly higher than that of the rubber composition E, containing the
control SAF type carbon black at various strain levels. Therefore the
rubber compositions F, G, and H demonstrate improved cornering and
handling stiffness as compared to rubber composition E.
Another very important property for high performance and racing tire tread
compositions is traction. High energy dissipation is required for high
traction. Loss modulus, G" is related to energy dissipation, with higher
G" values being indicative of higher energy dissipation. As shown above,
at 0.0 degrees C., the loss modulus, G", of the rubber compositions F, G,
and H, produced with the carbon blacks of the present invention are
significantly higher than the rubber composition, E, produced with the SAF
carbon black sample. These results demonstrate that higher traction can be
obtained by incorporating the carbon blacks of the present invention in
rubber compositions.
It should be clearly understood that the forms of the present invention
herein described are illustrative only and are not intended to limit the
scope of the invention. The present invention includes all modifications
falling within the scope of the following claims.
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